A mixture contains `O_(2) and N_(2)` in the proportion of 1:4 by weight. What will be the ratio of the number of molecules of `O_(2)` and `N_(2)` in the mixture?

Explanation

Let, the mass of the mixture be W g
`therefore` In the mixture, mass of `O_(2)=(W)/(5)g` and mass of `N_(2)=(4W)/(5)g`
`therefore`Number of gram-mole of `O_(2)=(W//5)/(32)=(W)/(160)` and
Number of gram-mole of `N_(2)=(4W//5)/(28)=(4W)/(140)`
So, number of `O_(2)` molecules`=(W)/(160)xx6.022xx10^(23)` and
Number of `N_(2)` molecules`=(4W)/(140)xx6.022xx10^(23)`
`therefore`The ratio of the number of molecules of `O_(2)` to the number of molecules of `N_(2)` in the mixture
`=(Wxx6.022xx10^(23))/(160):(4Wxx6.022xx10^(23))/(140)`
`=(1)/(160):(4)/(140)=14:64=7:32`